It's very hard to make estimates, all I know is that I've seen my Haswell go from 70W for
a non AVX prime95 to 140W instantaneous power consumption when heavily using AVX/FMA (of
course it had to turn down turbo after a few seconds). Of course translating that
experience to 14nm and a new design is dangerous.

Your own estimate claims slightly above 1W per core without taking AVX-512 into account or
100W for 72 cores again without AVX. I have a hard time believing an AVX-512 unit could
run in less than 1W at 2.6 GHz under heavy load.